1. Field of the Invention
The present invention relates to a light-emitting diode and its manufacturing method, and more particularly to a substrate type surface-mounted light-emitting diode (hereinafter simply abbreviated to LED) with a side emission and its manufacturing method, this surface-mounted LED including an LED chip mounted on a printed substrate such that the PN junction surface of the chip is perpendicular to the printed substrate surface.
2. Description of the Prior Arts
Conventional side-emitting LEDs include the following three types.
The first type is disclosed in Japanese Published Utility Model Application No. HEI1(1989)-163352. This LED is manufactured as follows. LED chips 101 are die-bonded to electrodes 102a and 102b on a relatively thick printed substrate 102, and wire-bonding is made using Au lines 103. Subsequently, molding is performed to form a mold resin portion 104, followed by dicing. Each LED chip 101 is uprighted for use (see FIG. 7). This type of LED is generally called a side-emitting LED.
The second type is disclosed in Japanese Published Unexamined Patent Application No. HEI1(1989)-283883. This LED is a surface-mountable type wherein a light-emitting portion is arranged sideways with respect to the LED chip 101 that is assembled in an insert-molded frame provided with a reflector 105 (see FIG. 8). The numeral 103 denotes an Au line.
The third type is disclosed in Japanese Published Unexamined Patent Application No. HEI10(1998)-125959. This LED is manufactured as follows. An LED chip (not shown) is die-bonded and wire-bonded on a relatively thin printed substrate 102. Then, the resultant is sealed with a dome-like transparent resin portion 106. The transparent resin portion 106 is then covered with a white resin portion 107 serving as a reflector, to thereby complete the LED (see FIG. 9). The LED emits light P101 from an opening 107a provided at the white resin portion 107.
The aforementioned three types of LEDs are obtained by using a general LED bare chip as it is.
However, these LEDs have the following problems. Specifically, the first type LED, although it is easy to make this LED thin, has a problem that the LED chip is proximal to the printed substrate where the chip should be mounted. It also has another problem that solder flux is permeated from the space between the mold resin and the substrate for the LED chip, to thereby pollute the LED chip.
The second and third types have a problem that it is difficult to make them thin since they have a structure including the reflector. The minimum thickness is about 0.8 mm.